Vacuum pump



Sept. 2, 1930. s, s 1,774,662

VACUUM PUMP Filed April 12, 1928 3 Sheets-Sheet 1 Sept. 2, 1930. 'A'. s. PARKS 1 1,774,662

VACUUM PUMP I Filed April 12, 192 3 Shasta-Sheet 2 Sept. 2, 1930. A] s, PARKS 1,774,662

VACUUM PUMP Filed April 12, 1928 3 Sheets-Sheet 3 56W: GfiZ/uLPS. parks -1 @wM gay 5.

Patented Sept. 2, 1930 PATENT OFFICE ARTHUR S. PARKS, OF SANDWICH, ILLINOIS VACUUM PUMP Application filed April 12, 1928.

This invention relates to pumps and more particularly to vacuum pumps.

The principal object of the invention is the provision of a new and improved vacuum pump provided with a novel arrangement of valves whereby a high vacuum may be produced.

Another object of the invention is the pro vision of a reciprocating vacuum pump provided with new and improved rotary valve means for controlling the suction and exhaust ports.

A further object of the invention is the provision of a reciprocating vacuum pump provided with new and improved rotary valves whereby a single port may be utilized as an intake and outlet portfor the pump cylinder.

A still further object of the invention is the provision of a vacuum pump having new and improved valve mechanism with a novel arrangement of ports for reducing the resistance to the flow of air to aminimum, whereby greater efliciency is obtained by the air exhausting mechanism;

Another object of the invention is the provision of a new and improved vacuum pump that is cheap to manufacture, easily assembled, simple and rugged in construction, efi'icient in operation, composed of few moving parts, and that is not likely to become broken or get out of order.

Other and further objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawings, in which 1g. 1 is a vertical section of the pump; Flg. 2 1s a section on l1ne 22 of Fig. 1; Fig. 3 1s a sectlon on l1ne 33 of Fig. 1;

Fig. 4 is a section on line H of Fig. 1;

Fig. 5 is a vertical section on line 55 of Fig. 3;

Fig. 6 is a bottom plan view of one of the valves; and

Fig. 7 is a perspective View thereof.

Serial No. 269,415.

Referring now to the drawings, the reference character 10 designates the pump casing which, as shown, comprises the two cylinders 11 and 12 in its upper portion and the crank case 13 in its lower portion. TVhile in the form of the device selected to illustrate one embodiment of the invention a two cylinder pump is disclosed, it is understood that this is by way of example only. The lower portion of the crank case is provided with a removable cover 1 1 for retaining oil within said crank case for lubricating the mechanism, by the splash system, in the usual manner.

The opposite sides of the casing 10 are provided with enlarged alined openings 15 and 16 for receiving the anti-friction bearing supports 17 and 18. The support 17 is provided with a cylindrical portion 19 which is adapted to engage in the opening 15 and is providedwith a flange 21 for securing the support to the casing as by means of screws or the like in a manner well known in the art. The support 17 is hollow and is provided with an inner annular flange 22 for forming an outer limiting stop for an antifriction bearing 23, the inner race 24 of which is secured to one end of a crank shaft 25 which extends axially outwardly through said support 17. The outer race of said bearing is secured in the opening in the inner end of said support 19 in contact with said flange or shoulder 22.

The support 19 extends laterally outwardly to form a recess 26 for receiving oil passing through the antifriction bearing 23. A conduit 27 in said support and the pump casing conducts the oil from said recess 26 back into the reservoir or crank case 13. If desired, a collar 28 having a sharp peripheral edge for causing the oil to flow therefrom by gravity may be mounted on said shaft for limiting the outward movement of the oil along said shaft. An oil retaining ring '31 of the usual construction may be mounted in the outer end of the support 19 and is retained in position against th annular shoulder 32 by a sprmg ring "3 as is usual in such constructions.

The opposite end of the crank shaft is provided with anti-friction bearings secured in the support 18, the parts being held from moving outwardly by the plate 31, which may be and preferably is integral with said support 18.

By means of this arrangement the crank shaft 25 may be readily inserted or removed from the crank case through the enlarged opening 15 or 16.

The crank shaft 25 is provided with two crank arms and 36 arranged 180 apart. Suitable connecting rods 37 and 38 have their lower ends connected to the crank arms and 36, respectively, and their upper end connected to the pistons 39 and -11 respectively, for reciprocating the same within the cylinders 11 and 12, in the usual. manner. The pistons 33* and a1 make a close lit within the cylinders 11 and 12 and they are provided with the piston rings 12 is usual in such constructions.

Suitable .inlct and outlet ports with airtight val are provided for the cylinders. As shown, the cylinders 11 and 12 are provided with ahead which is in the form of a plate 613. The plate -15 is provided with oppositely arranged arcuate recesses all. and -15, see Fig. -l-, in the upper surface of said plate, which are in communication with the cored passa es 18 and *1? respectively, which converge into the common inlet passage 18 lead ing laterally out vardly to the passage -19 leading to the vessel from which the air is being er-zhausted. The plate 4:3 is also provided with openings 51 and above the cylinders 11 and 1.2, respectively. The openings 51 and constitute both the inlet and outlet ports for the cylinders, as will presently appear. They may be and preferably are inclined so that they will not only miss the cylinder walls, but will terminate adjacent to the central portion of the cylinder, whereby the frictional resistance between the cylinder walls and the dischargimgg air will be reduced to a minimum.

The valve mechanism for controlling the ports or openings 51 and 59. will now be described. The valves and, their operatin mechanism are mounted on the plate 1;; and are enclosed within a valve casing or housing 53 within which the air from the cyliruleis is exhausted. the air passing out through the 5-1, see Fi -s. 1 and 2. The casing 53 is held in position by bolts passing upward through a flange on the cylinders, and through the head, and tapped into said casing. Dowel pins position the head.

A pair of substantially circular rotary val es 55 and 56 are provided for controlling the passages 51 and 52. These valves are rotatably mounted on posts 57 and 58, respec tively, which are secured at their lower ends in openings 59 and (3.1 in the cylinder head 13, and their upper ends rigidly secured to the casing 53 by the pins 10 and 50 which extend through said casing into the ends of said posts. These openings are coaxial with the arcuate recesses 1 1 and 45. Each valve is provided with a segmental recess or cavity 62 having an extension 63 extending about the hub 61. Each valve is also provided with an arcuate opening or slot 65 opposite the recess 62. The extension 63 of the recess 62 is of less radial distance from the hub 61- than the openings 51 and 52 in the cylinder head 13 whereby when either rotary valve is in the same relative position as the valve 56 the opening or slot 65 alone will be in communication with the opening see Fig. 1, thereby placing the cylinder 12 in communication with the exhaust passage 54 through the openings (35 and the interior of the casing 53, the inlet 15 being closed by the recessed portion of the valve. The air within the cylinder 12 will therefore be forced out as the piston 11 ascends. \Vhen the valve is turned through 180 it will assume the same relative position as the valve f5, as shown in Fig. 1.

111 this position. the inlet passage 11, see Figs. 1 and 4-, is in communication with the cylinder 11 through the recess 62 and its extension (33 whereby air will be drawn into the cylinder 11 through the intake passages d l, 46, 4:8 and 19 when the piston 39 is moving down, shown in Fig. 1.

It will thus be seen that as air is drawn into one cylinder it is simultaneously es:- pelled from the other, and vice versa.

Suitable means are provided for operating the Valves 55 and 56. This means is adapted to rotate the valves continuously and simultaneously in one direction. Any suit able means may be employed for this purpose. As shown, the valves are operated from the crank shaft by a countershaft 67 the lower end of which is provided with a worm wheel (38 which is adapted to be rotated by a worm gear 69 secured to the c 'ank shaft 25. F or convenience of assembly the crank shaft may be divided and the parts connected together by a stud 71 on which the worm gear (39 is mounted. The adjacent ends of the shaft are provided with disks 72 and 73 which are adapted to be clamped against the worm gear 69 in any suitable manner as by means of the bolts T1.

The lower end of the shaft 67 isrotatably mounted in the sleeve bearing 75 secured in an opening in the boss 76 on the inner surface of the crank case. A lug 79 secured to the lower end of the shaft 67 is provided with a recess for receiving a ball bearing 78 which engages the end of a plug 77 thread ed in the boss 76. The upper end of the plug loo 77 is flat so that even if the shaft 67 is not properly centered it will not affect the ball bearing.

The upper end of the shaft extends through a bushing or sleeve bearing in the head 43 and is also provided with a bearing plug 84 having a recess therein for receiving the ball bearing 83 which in turn engages the flat end of the screw-threaded plug 82. A suitable lock nut holds the plug 82 in adjusted position. By means of these arrangements the shaft 67 is mounted on ball bearings and the bearings may be adjusted by the plugs 77 and 82 as is obvious from an inspection of Fig. 2.

Mounted within the casing 53 on the upper ends of the shafts or pins 57 and 58 are the gear wheels 85 and 86 respectively. Each of these gear wheels is provided with studs or pins 87 and 88, see Figs. 2 and 5, which are adapted to engage in recesses in the valves and 56 for causing said valves to rotate in unison with the corresponding gear wheels.

In order to hold the valves 55 and 56 in contact with the upper surface of the cylinder heads so as to prevent the escape of air between the valves and the cylinder head, suitable springs 89 are mounted on the pins 87 and 88 between the gear wheels 85 and 86 and said valves. The contacting surface of the head and valves is properly ground to form an airtight connection.

The gears 85 and 86 are of the same diame ter and have the same number of teeth and are adapted to mesh with a gear 91 secured to the upper end of the shaft 67 for rotating said gears and said valves, in timed relation.

By providing the extension 63 on the segmental recess 62 as extending through almost 180, and forming the terminals of the intake passages in the form of arcuate slots 44 and 45, see Figs. 4:, 6 and 7, the intake is held open a maximum period during each rotation of the valve, whereby air is free to flow into said cylinders during almost the entire downward movement of the pistons, thereby greatly increasing the efficiency of the pump.

By the use of a single circular opening in the head 43 and by making said head comparatively thin, a minimum amount of residual air will be trapped therein when the piston has reached the upper limit of its travel and the valve has closed said opening preparatory to placing said opening in communication with the exhaust port in said valve, whereby the efliciency of said pump is greatly increased.

The parts are also so constructed that there is but a small clearance between the head plate 43 and the piston in its uppermost position, whereby practically all of the air except a very small amount in the openings 51 or 52 is discharged from each cylinder at each upward stroke of the pistons.

The device is lubricated by the splash system in the usual manner,-that is, the rods 37 and 38 are provided with dippers or .fingers 98 which come in contact with the oil in the bottom of the crank case and splash the same on'the different bearings, a portion being forced upwardly through the passages 99 for lubricating the crank hearings in the usual manner.

The oil being splashed on the cylinders and pistons will make an airtight joint therebetween, and the oil escaping along the cylinder walls and the shaft 67 will properly lubricate the valves and valve operating mechanism in the casing 58. Particles of oil will find their way between the valves and the cylinder head, thereby forming an airtight joint at these points.

It is thought from the foregoing taken in connection with the accompanying drawings that the construction and operation of my device will be apparent to those skilled in the art, and that various changes in size, shape, proportion and details of construction may be made without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a pump, a casing having a plurality of cylinders and a single valve chamber therein, a piston for each cylinder, said casing having a common intake and exhaust port for each of said cylinders, a rotating valve for each port, and means for operating said valves in timed relation.

2. In combination, a cylinder block, a plurality of cylinders in said block, a piston for each cylinder, a valve chamber, a single passage leading from each of said cylinders to said chamber, a single intake passage, a single discharge passage, valves within said chamber and means for operating said valves to alternately place said discharge and intake passages in communication with the passages leading to said cylinders.

3. In a vacuum pump, a casing, a. plurality of cylinders in said casing, pistons in said cylinders, a crank shaft for operating said pistons, a valve chamber, valve seats, a single port in each seat, a passageleading from each of said ports in each of said seats, respec tively, to a corresponding cylinder, an intake passageleading to a vacuum chamber, an e);- haust passage, a pair of rotating valves for placing said ports alternately in communication with said intake and exhaust passages.

4. In a vacuum pump, a pair of cylinders,

pistons in said cylinders, a crank shaft for operating said pistons, a gear on said shaft, an exhaust conduit, a valve chamber, a valve shaft in saidchamber, valve seats within said chamber having ports in communication with said conduit and cylinders, valves for controlling the passage of air through said ports, a gear on said valve shaft adapted to be rotated by the gear on said crank shaft, gears for rotating said valves from the gear on said valve shaft, and resilient means between said last named gears and each of said valves for holding said valves against said seats.

5. Valve mechanism for a pump comprising a valve casing, a valve shaft within said casing, valve seats in said casing, valves for engaging said seats. an operating gear on said shaft, a pair of gears operated by said [irst named gear, and means for detachably connecting said valves to said last named gears for rotating said valves.

6. In a pump, a casing, a plurality of cylinders within said casing. a piston for each cylinder, a crank shaft within said. casing for reciprocating said pistons, a cylinder head within said casing for said cylinders, ports in said head, a rotary valve for each port, means including a single shaft for rotating said valves in timed relation from said crank shaft, and a valve casing for enclosing said valves.

7. In a vacuum pump, a cylinder, a piston. means for reciprocating said piston in said cylinder, a cylinder head, a single opening through said head, said head being provided with a recess in conm'iunication with an intake passage, a movable valve over said opening and recess, said valve having a recess on its lower face for placing said recess and slot in said head in communication with eaca other for the passage of air from said intake passage into said cylinder, and having an opening therethrough for registering with the opening in said head for the passage of air from said cylinder. and means including a gear, laterally extending pins on said gear for engaging corresponding openings in said valve for moving said valve in timed relation to the operation of said piston.

8. In a pump, a pair of cylinders, a re ciprocating piston within each cylinder. means for moving the pistons in opposite direct-ions, a valve chamber at one end of the cylinders, a single passage connecting each cylinder with the chamber through its floor, a passage opening outwardly from the chamber above its floor, two passages opening outwardly from the chamber through its floor, a pair of rotary valves seated on the floor of the chamber and each having an unobstructed through port and a cavity in its lower face, means for rotating the valves in timed relation to each other and with the pistons for alternately bringing the passage and cavity of each into communication with the passage to the cylinder with which it is associated.

9. In a combined air compressor and vacuum pump, a casing having an oil compartment in its lower portion and provided with a cylinder in its upper portion, a piston for said cylinder, a crank shaft rotatably mounted in said con'ipartment for operating saie piston, an oil retaining member on said shaft,

signature.

ARTHUR S. PARKS. 

